What Is a VPN Passthrough?

If you use a VPN just to guard your privacy online or unblock geo-restricted websites, it’s not necessary to know about VPN passthrough. It’s a networking feature that allows some VPN connections to pass through routers. As you can guess, that is where it gets its name from.

If you use the OpenVPN protocol and have a Wi-Fi router bought in the last five years, you don’t even need to worry about VPN passthrough. It only applies to outdated VPN protocols and older routers. 

However, it is good to have a basic understanding of VPN passthrough if you ever have to troubleshoot your VPN software or router. Here’s a quick rundown.

VPN Passthrough: What Is It?

VPN passthrough is a router setting that can identify and allow VPN connections of older protocols like IPSec and PP2P. It’s a default feature in all modern network routers and modems, which makes creating firewalls and encrypted tunnels possible.

However, that is not the case with older routers (consider pre-2010 as a ballpark). In them, an IP mapping system called Network Address Translation (NAT) disallows all VPN connections. This happens due to NAT’s configuration where it changes the IP address of the incoming connection. Even if the link from your device comes out encrypted, the meddling router fails to understand it. This NAT action affects VPNs, making them pointless in such routers.

It should be noted that only older VPN protocols such as IPSec, L2TP, and PP2P face this issue in older routers. This is because such routers lack VPN passthrough. OpenVPN and WireGuard are immune to NAT’s actions. 

Routers sold today come with built-in VPN passthrough, making it a lot smoother for VPN connections to pass through them. If you are using a new router and have tuxlerVPN installed, you don’t have to do anything.

Uses of VPN Passthrough

Now that you have a basic idea of VPN passthrough, let’s take a look at its potential uses. Here are the common uses of the VPN passthrough feature:

• Allow VPN connections on older protocols like IPSec
• Allow VPN connections on older, outdated routers or modems
• Set up a firewall on your router
• Create a do-it-yourself VPN software for personal use

As noted above, if you use tuxlerVPN with a Wi-Fi router that was purchased a few years ago, you don’t have to do anything. In most cases, if your VPN is working fine (test it this way), you don’t have to worry about passthrough. However, if you wish to check your router’s compatibility, go to your router settings and look for the Network Security option. Toggle on all related pass-throughs (some routers may have individual settings for every protocol).

VPN passthrough may not be a relevant concept for general users but it’s good information to have should there be a need in the future. For more informational guides on virtual private networks, keep following our blog.

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